Yes, it does have RPM sensing.

I have a acer aspire x1430g tower. It only has a small cpu fan, and the same size exhaust fan.. So I bought a 120mm fan for intake on the side of the case but didn't realize it has "Round" pin holes.

Do you know if there is an adapter I can buy? Or? I only paid $4 for the fan so it's not like I'm out anything but would still like to use it.